Rotary furnace grate



L. TREFOIS. ROTARY FURNACE GRATE.

APPLICATION FILED MAR. 4. 1920.

. 1,427,338. Patented Aug. 29, 1922.

IN VEN TOR LEo/v mFcvs flfTORNEY .fication. 1

r' aranr orrica- Ln'on rnnrors, or BnussELsBnLGIui/L oreas reunites GRATE.

Application filed March 4, 1920. Serial No. 383,329..

' Specification of Letters Patent. Patrgnt gd Aug;

- (GRANTED UNDER msmwsmm or THE Aer OF MARCH a, 1921, eisrar. n, 1313.) I

To all whom-it may concern .1 y

' Be it known that 1.; LI J ON TiiFOISflSub- ,ject of Belgium. residing at Brussels,. Belgium have invented new and useful lmprovemen ts in Rotary Furnace Grates, (for which I havefi-led application in e in. Germany August 1.3, 1.918. Patent No. 33"?,Tetl.; France, March 22 1919, PatentNo. 497.437;

and England; October 1 1,, 1919,P;atent-.No.

153,163) of which" the following is speci- This invention has for its objects rotary grate comprising a plurality of concentric rings turning in opposite. directions relatively to each other and providedwith regularly spaced slots, covered by. auxiliary grates. formed by perforated or gridlilte bridges, the sides of which arranged towards the vdirection of motion "are open for the discharge .ol the ashes. k

The improved grate is shown by way of example in the accompanying drawing:

Figure 1 is a diagrammatic.view'iu ver tical section of the grate; the part at the left hand side assumes the auxiliary, grates .to be removed, whilst the part onthe right hand sideshows the concentric grate rings surmounted by auxiliary grates.

; Figure 2 is aplan. view, showing all the slots or holes in the grate rings. (the auxiliary grates: being removed) and the direction of 'rotation.

.Figure -3 shows, to a larger scale, a .portion a. grate, ring provided with its auxiliary. grates.

Figure 4 is a fragmentary vertical section through an auxiliary grate and the main grate- Figure 5is a partial bottom planview of the concentric grate rings and discloses the edge of each ring as being provided with a toothed. section cooperating with pinions carried on rods which operatefrom a rotat- I ing. drive shaft;

. The grates: are composed of two quite distinctparts, the maingrates on the one hand and the auxiliary grates on the other hand.

The main grates are 'formed by aseries of concentric rings A, each providedv with a discharge incline. The outer grate ring B is provided with a downwarclly inclinedperipheral flange B constitut ng a chute for the, discharge of ashes into the lower part Bel giuin Theniain grate rings rotate on ings. I V the grate rings accompany the latter in their leftopen at the front.

of the body of the'hearth of furnace. Each ring turns in the opposite direction .to those adJacentto it; the number ofrings-varies with the size of the apparatusflto which the perforated or may be of gridlike form and is permanently fixed on the corresponding main grate ring. M ball bear- The auxiliary grates being fixed to rotary niotion. .As'the rotationofany ring A considered, always takes place'in the same direction theauxiliary gratesare closedat the sidesfand at. the rear. being thus' only auxiliary grates are made of gridlike or perforated form so as toprevent theperinanent fall of? the ashes, whilst leaving the passageflfree for the air forsupportiugcom- .bustlon. This arrangement which reduces the space taken up by an auxiliary, grate enables the number of auxiliary grates to be increased. and consequently increases the efiiciency of the apparatus. 1 When at rest, the ashes thus enter the aperture at the front of the auxiliary grate (see Figure 4:)

body drives the lower layer into the space inthe auxiliary grate. The auxiliarygrates thus serve scrapers and whenone of them,

i by reason of its rotation, has taken the place I which its neighbor occup ed before the movement. a complete s11 ce or layer of ash has been cut oif over the whole surface.

The outer grate ring B likewise discharges its contents down thechute B by reason of the rotary motion. o

The central grate ring D, which is also rotary.,is .freed from the ashes thereon by the effect of the rotary motion. The ashes which lie between the annular spaces served by the auxiliary grates are discharged through the spaces left between the two rings Aby the eflect of. the rotary motion. I From these arrangements as a whole it results that the whole surface of the grate is regularly cleaned and regularly supplied The walls of the a with air for combustion, this air being distributed equally well through the gridlike walls of the auxiliary grates as through the ashes which form the discharge slopes in the auxiliary grates and in the main grate rings.

As shown in Figure 5 the sectors are operated by a mechanism which -o1nprises a hub mounted axially of the grate and a pair of radially disposed shafts b and 6 supported in suitable bearings on the hub. The grate rings A and B are provided with toothed sections 10 cooperating with pinions p and p carried by the shafts Z) and 7) respectively, the said pinions being so arranged that alternate sections 10 are engaged by the pinions of the same shaft. The opposite ends of the shafts b and 7) carry worm wheels 1' and 7* respectively, which mesh with worm gears u and M respectively, mounted on a drive shaft (1. By reversing the pitch of the worm wheels 7" and r the shafts b and b may be made to rotate in opposite directions, in which case alternate grate rings will rotate in the same direction and in opposite direction to adjacent rings.

The use of grates with a plurality of concentric zones has for its result the distinctive features and advantages set forth below:

1.The division of the grate into concentric rings turning in opposite directions relatively to each other, so as to prevent the driving round of the whole mass of fuel in the producer or on the hearth.

2.The discharge of the ashes by the effect of the rotary motion, these ashes passing along discharge slopes provided between the rings and along the external slope of the grate ring B. It should be remarked that the rotary motion has here only to work on narrow spaces, from which results its efficiency.

3.The possibility of varying the intensity of the cleaning action from one place to another by varying the speed of one or more of the concentric rings.

On the other hand, the application of grates with slots or divided grates and fixed auxiliary grates produces the following distinctive features and advantages:

l.The discharge of the ashes through the slots formed in the main grates.

2.The covering of these slots by the auxiliary grates.

3.The method. of working of the auxiliary grates which act as scrapers and cut a slice or layer from. the ashes.

4.The fact that when an auxiliary grate, by reason of the rotary motion, has occupied the place whlch 1ts neighbour occupied before the movement, a complete slice of the ashesh'as been cut over the whole surface. Th a n ages which result from the other method (a) Formation of air-passages or holes in the fire due to localized supply of air 18 rendered impossible, the air passing in at all places at the same time.

(6) Burning of the fuel over a maximum surface permitting uniform, rapid and complete combustion.

2.Scientific discharge of the ashes ob tained by the large number of apertures through which the ashes can pass (a) Uniform removal of the ashes causes perfect regularity of combustion over the whole surface, which may thus be increased without disadvantage, thus enabling apparatus of larger diameter to be constructed.

(7)) The uniform removal of the ashes prevents the formation of air passages or holes in the fire due to the presence of ashes in the mass of fuel, a disadvantage which is liable to occur with all other arrangements.

I claim 1. A rotary furnace grate comprising a plurality of concentric perforated grate rings, said rings being provided with downwardly projecting means for discharging ashes therefrom, mechanism for rotating adjacent rings in opposite directions relatively to each other, and an auxiliary grate over each perforation in said grate rings and movable with its respective grate ring in a circular path through the under surface of the fire bed, said auxiliary grate comprising a foraminous casing having an end opening which faces the direction of rotation thereof.

2. In a rotary furnace grate, the combination of a plurality of concentrically disposed perforated grate rings having inclined discharge flanges projecting from the under surfaces thereof, means for rotating the adjacent grate rings in opposite directions relatively to each other, and auxiliary grates carried by said rings above said perforations respectively to form circular series of scrapers movable. through. paths cut by themselves into the under surface of the fire bed, said auxiliary grates comprising foraminous casings having their ends open which face in the direction of rotation thereof, whereby material scraped from the under surface of the fire bed will fall into the paths of travel of the open ends of the auxiliary grates and pass through the said opening to the grate rings and thence through the perforations in the latter to the discharge flanges.

3. In a rotary furnace grate, the combination of aplurality of concentrically disposed perforated grate rings, mechanism for rotating the adjacent grate rings in opposite directions relatively to each, and an auX- In testimony whereof I have signed my ihary grate over each perforation and sename to this specification 1n the presence of cured to a grate ring, said auxlhary grate two s ub scrlbmg witnesses.

comprising a segmental foraininous casing LEONTREFOI$. provided with an ash receiving open ng in Wit e the front end facing the dlrection of rota- LOUIS JOFFIN tion of its respective grate ring. i F W ROLAND 

